1. Field of the Invention
The present invention relates to a terminal structure, a printed wiring board, a module substrate, and an electronic device.
2. Related Background Art
Package substrates made by connecting module substrates mounted with various electronic components to a motherboard and the like have been in use for electronic devices. Typically, such a module substrate is connected to the motherboard by solder-joining terminals on its surface to conductor sections of the motherboard, whereby the electronic components mounted on the module substrate are allowed to function.
From the viewpoint of securing reliability in the electronic devices such as those mentioned above, it is required that the connection between the module substrates and the motherboard and the connection between the electronic components and module substrates be hard to break. Therefore, the module substrates and the like used for connecting with the motherboard and terminals forming their joints are demanded to be excellent in solder joint strength which is evaluated by a solder ball pull test. In response to such demands, it has been proposed to optimize the composition and thickness of plating films disposed on surfaces of terminals (see, for example, Japanese Patent Application Laid-Open No. 2008-177261).